U.S. patent number 9,920,732 [Application Number 14/370,287] was granted by the patent office on 2018-03-20 for engine starting device and engine automatic stop and restart control device.
This patent grant is currently assigned to Nissan Motor Co., Ltd.. The grantee listed for this patent is Nissan Motor Co., Ltd.. Invention is credited to Motoyuki Hattori, Yuuichi Hosaka, Takayuki Iwasaki, Ryo Sano, Hiromoto Shimizu.
United States Patent |
9,920,732 |
Shimizu , et al. |
March 20, 2018 |
Engine starting device and engine automatic stop and restart
control device
Abstract
An engine starting device is provided with a battery, a starter
motor, an inrush current limit circuit and a control unit. The
inrush current limit circuit has a resistor and a bypass relay
connected in parallel. The inrush current limit circuit is
interposed between the battery and the starter motor. The bypass
relay has a normally open contact that is configured to be closed
at a time of engine startup. The control unit is programmed to
include a fault identification unit that identifies a location of
fault occurrence in the inrush current limit circuit based on a
minimum voltage of the battery existing while the starter motor is
determined to be in operation and an amount of decrease in voltage
of the battery existing while the normally open contact is
determined to be actuated in a closing direction.
Inventors: |
Shimizu; Hiromoto (Yokohama,
JP), Iwasaki; Takayuki (Yokohama, JP),
Sano; Ryo (Kawasaki, JP), Hattori; Motoyuki
(Atsugi, JP), Hosaka; Yuuichi (Kawasaki,
JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Nissan Motor Co., Ltd. |
Yokohama-shi, Kanagawa |
N/A |
JP |
|
|
Assignee: |
Nissan Motor Co., Ltd.
(Yokohama, JP)
|
Family
ID: |
48947487 |
Appl.
No.: |
14/370,287 |
Filed: |
February 5, 2013 |
PCT
Filed: |
February 05, 2013 |
PCT No.: |
PCT/JP2013/052614 |
371(c)(1),(2),(4) Date: |
July 02, 2014 |
PCT
Pub. No.: |
WO2013/118724 |
PCT
Pub. Date: |
August 15, 2013 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
|
US 20140372013 A1 |
Dec 18, 2014 |
|
Foreign Application Priority Data
|
|
|
|
|
Feb 9, 2012 [JP] |
|
|
2012-026076 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
F02N
11/108 (20130101); F02N 11/0818 (20130101); F02N
15/00 (20130101); H02H 9/002 (20130101); F02N
11/087 (20130101); F02N 11/08 (20130101); F02N
11/0814 (20130101); F02N 2200/102 (20130101); F02N
2200/101 (20130101); Y02T 10/40 (20130101); F02N
15/067 (20130101); Y02T 10/48 (20130101); F02N
2250/02 (20130101); F02N 2200/0807 (20130101); F02N
2300/2011 (20130101); F02N 11/0862 (20130101) |
Current International
Class: |
F02N
11/08 (20060101); H02H 9/00 (20060101); F02N
15/00 (20060101); F02N 11/10 (20060101); F02N
15/06 (20060101) |
Field of
Search: |
;701/29.1,29.2,112,113,114 ;123/179.3,179.4 ;290/38R |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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101832209 |
|
Sep 2010 |
|
CN |
|
2000134707 |
|
May 2000 |
|
JP |
|
2004-257369 |
|
Sep 2004 |
|
JP |
|
2006081340 |
|
Mar 2006 |
|
JP |
|
2008301612 |
|
Dec 2008 |
|
JP |
|
2011014282 |
|
Jan 2011 |
|
JP |
|
2011-185260 |
|
Sep 2011 |
|
JP |
|
WO 2011158088 |
|
Dec 2011 |
|
JP |
|
Primary Examiner: Gimie; Mahmoud
Assistant Examiner: Zaleskas; John
Attorney, Agent or Firm: Global IP Counselors, LLP
Claims
The invention claimed is:
1. An engine starting device comprising: a starter motor; a
battery; an inrush current limit circuit comprising a resistor and
a bypass relay connected in parallel, the inrush current limit
circuit interposed between the battery and the starter motor, the
bypass relay having a normally open contact that is configured to
be closed at a time of engine startup; and an engine control unit
programmed to detect a minimum voltage of the battery existing
while the starter motor is determined to be in operation and to
detect an amount of decrease in voltage of the battery existing
while the normally open contact is determined to be actuated in a
closing direction, the voltages used by the detections being
different voltages; the engine control unit being programmed to
include a fault identification unit that identifies a location of
fault occurrence in the inrush current limit circuit upon the
engine control unit determining the detected minimum voltage of the
battery existing while the starter motor is determined to be in
operation is less than a first predetermined amount and upon the
engine control unit determining the detected amount of decrease in
voltage of the battery existing while the normally open contact is
determined to be actuated in the closing direction is less than a
second predetermined amount, the engine control unit being further
programmed to enable automatic stopping and restarting of an engine
and to prevent the automatic stopping and restarting of the engine
when the fault identification unit identifies the location of fault
occurrence.
2. The engine starting device according to claim 1, wherein the
fault identification unit identifies the location of fault
occurrence through a comparison with a pre-recorded normal battery
voltage waveform at the time of engine startup.
3. The engine starting device according to claim 2, wherein the
fault identification unit is programmed to identify the bypass
relay as being stuck in an open state when the minimum voltage of
the battery is greater than a predetermined voltage and the amount
of decrease in the voltage of the battery is equal to or less than
a predetermined amount of decrease in the voltage.
4. The engine starting device according to claim 2, wherein the
fault identification unit is programmed to identify the bypass
relay as being stuck in a closed state when the minimum voltage of
the battery is equal to or less than a predetermined voltage and
the amount of decrease in the voltage of the battery is equal to or
less than a predetermined amount of decrease in the voltage.
5. The engine starting device according to claim 2, wherein the
fault identification unit is programmed to identify a disconnection
in the resistor when the minimum voltage is equal to or less than a
predetermined voltage and the amount of decrease in the voltage is
greater than a predetermined amount of decrease in the voltage.
6. The engine starting device according to claim 2, wherein the
engine control unit is further programmed to include an automatic
stop and restart prohibition unit for prohibiting automatic
stopping and restarting of the engine and alerting a driver when
the location of fault occurrence is identified by the fault
identification unit.
7. The engine starting device according to claim 6, wherein the
engine control unit is further programmed to include a fault
information recording unit that records information representing
the fault location identified by the fault identification unit, and
the automatic stop and restart prohibition unit is programmed to
maintain the prohibition of automatic stopping and restarting of
the engine and to maintain the alerting of the driver until
information representing the fault location is deleted after the
fault location has been repaired.
8. The engine starting device according to claim 1, wherein the
fault identification unit is programmed to identify the bypass
relay as being stuck in an open state when the minimum voltage of
the battery is greater than a predetermined voltage and the amount
of decrease in the voltage of the battery is equal to or less than
a predetermined amount of decrease in the voltage.
9. The engine starting device according to claim 8, wherein the
fault identification unit is programmed to identify the bypass
relay as being stuck in a closed state when the minimum voltage of
the battery is equal to or less than the predetermined voltage and
the amount of decrease in the voltage of the battery is equal to or
less than the predetermined amount of decrease in the voltage.
10. The engine starting device according to claim 8, wherein the
fault identification unit is programmed to identify a disconnection
in the resistor when the minimum voltage is equal to or less than
the predetermined voltage and the amount of decrease in the voltage
is greater than the predetermined amount of decrease in the
voltage.
11. The engine starting device according to claim 8, wherein the
engine control unit is further programmed to include an automatic
stop and restart prohibition unit for prohibiting automatic
stopping and restarting of the engine and alerting a driver when
the location of fault occurrence is identified by the fault
identification unit.
12. The engine starting device according to claim 11, wherein the
engine control unit is further programmed to include a fault
information recording unit that records information representing
the fault location identified by the fault identification unit, and
the automatic stop and restart prohibition unit is programmed to
maintain the prohibition of automatic stopping and restarting of
the engine and to maintain the alerting of the driver until
information representing the fault location is deleted after the
fault location has been repaired.
13. The engine starting device according to claim 1, wherein the
fault identification unit is programmed to identify the bypass
relay as being stuck in a closed state when the minimum voltage of
the battery is equal to or less than a predetermined voltage and
the amount of decrease in the voltage of the battery is equal to or
less than a predetermined amount of decrease in the voltage.
14. The engine starting device according to claim 13, wherein the
fault identification unit is programmed to identify a disconnection
in the resistor when the minimum voltage is equal to or less than
the predetermined voltage and the amount of decrease in the voltage
is greater than the predetermined amount of decrease in the
voltage.
15. The engine starting device according to claim 13, wherein the
engine control unit is further programmed to include an automatic
stop and restart prohibition unit for prohibiting automatic
stopping and restarting of the engine and alerting a driver when
the location of fault occurrence is identified by the fault
identification unit.
16. The engine starting device according to claim 15, wherein the
engine control unit is further programmed to include a fault
information recording unit that records information representing
the fault location identified by the fault identification unit, and
the automatic stop and restart prohibition unit is programmed to
maintain the prohibition of automatic stopping and restarting of
the engine and to maintain the alerting of the driver until
information representing the fault location is deleted after the
fault location has been repaired.
17. The engine starting device according to claim 1, wherein the
fault identification unit is programmed to identify a disconnection
in the resistor when the minimum voltage is equal to or less than a
predetermined voltage and the amount of decrease in the voltage is
greater than a predetermined amount of decrease in the voltage.
18. The engine starting device according to claim 1, wherein the
engine control unit is further programmed to include an automatic
stop and restart prohibition unit for prohibiting automatic
stopping and restarting of the engine and alerting a driver when
the location of fault occurrence is identified by the fault
identification unit.
19. The engine starting device according to claim 18, wherein the
engine control unit is further programmed to include a fault
information recording unit that records information representing
the fault location identified by the fault identification unit, and
the automatic stop and restart prohibition unit is programmed to
maintain the prohibition of automatic stopping and restarting of
the engine and to maintain the alerting of the driver until
information representing the fault location is deleted after the
fault location has been repaired.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a U.S. National stage application of
International Application No. PCT/JP2013/052614, filed Feb. 5,
2013, which claims priority to Japanese Patent Application No.
2012-026076 filed in Japan on Feb. 9, 2012.
BACKGROUND
Field of the Invention
The present invention relates to an engine starting device and an
engine automatic stop and restart control device.
Background Information
Japanese Laid-Open Patent Application No. 2004-257369 discloses an
engine starting device in which an inrush current limit circuit,
comprising a resistor and a bypass relay connected in parallel, is
interposed between a battery and a starter motor, and a normally
open contact of the bypass relay is closed after a predetermined
time has elapsed after the engine is started, whereby a decrease in
the battery voltage during engine startup is suppressed.
SUMMARY
In the above engine starting device, there was demand for an
ability to identify the location of fault occurrence in the inrush
current limit circuit. An object of the present invention is to
provide an engine starting device and an engine automatic stop and
restart control device capable of identifying the location of fault
occurrence in an inrush current limit circuit.
In the present invention, the location of fault occurrence in an
inrush current limit circuit is identified, at engine startup,
based on the minimum voltage of a battery while the starter motor
is in operation and the amount of decrease in the voltage of the
battery when the normally open contact of the bypass relay is
actuated in the closing direction.
A disconnection occurring in a resistor, or a normally open contact
of a bypass relay becoming stuck, affects the minimum voltage of
the battery while the starter motor is in operation and the amount
of decrease in the voltage of the battery when the normally open
contact of the bypass relay is actuated in the closing direction.
Therefore, looking at the minimum voltage and the amount of
decrease in the voltage makes it possible to identify the location
of fault occurrence in the inrush current limit circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
Referring now to the attached drawings which form a part of this
original disclosure:
FIG. 1 is a system diagram showing a vehicle driving system
according to a first embodiment;
FIG. 2 is a circuit configuration diagram of an engine starting
device according to the first embodiment;
FIG. 3 is a time chart showing the inrush current limiting action
performed by the inrush current limit circuit according to the
first embodiment;
FIG. 4 is a flow chart showing the flow of a bypass relay fault
diagnosis process performed by a fault identification unit
according to the first embodiment;
FIGS. 5A to 5C are a time charts showing the power supply voltage
waveform according to each of the fault patterns in the first
embodiment; and
FIG. 6 is a list of fault modes, bypass relay states, and voltage
waveforms during normal operation and when a fault is present in
the first embodiment.
DETAILED DESCRIPTION OF THE EMBODIMENTS
A preferred embodiment of the engine starting device and the engine
automatic stop and restart control device according to the present
invention will now be described with reference to the embodiments
shown in the accompanying drawings.
First, the configuration of a first embodiment will be described.
FIG. 1 is a system diagram showing a vehicle driving system
according to the first embodiment. A rotary driving force inputted
from an engine 1 is inputted through a torque converter 2 into a
belt-type continuously variable transmission 3, changed in speed
according to a predetermined transmission ratio, and transmitted to
a driving wheel 4.
The engine 1 has a starting device 1a for performing engine
startup. Specifically, the starting device 1a is provided with a
starter motor, and performs engine cranking and injects fuel based
on an engine startup command, and stops the starter motor once the
engine 1 is able to self-rotate.
The torque converter 2 is provided to the output side of the engine
1, with the torque converter 2 having a lockup clutch which
amplifies the torque at a stop-speed range and prevents relative
rotation at a predetermined vehicle speed (e.g., about 14 km/h) or
above. The belt-type continuously variable transmission 3 is
connected to the output side of the torque converter 2. The
belt-type continuously variable transmission 3 comprises a starter
clutch, a primary pulley and a secondary pulley, and a belt
extended across the two pulleys, and changes the pulley groove
width by hydraulic control to achieve the desired transmission
ratio. An oil pump driven by the engine 1 is provided in the
belt-type continuously variable transmission 3. When the engine is
in operation, the hydraulic pressure from the oil pump feeds the
lockup clutch pressure and the converter pressure for the torque
converter 2, and also feeds the clutch engagement pressure and the
pulley pressure for the belt-type continuously variable
transmission 3. In addition, an electric oil pump 3a is provided to
the belt-type continuously variable transmission 3. When the
feeding of hydraulic pressure by the oil pump is no longer possible
due to automatic stopping of the engine, the electric oil pump 3a
operates and feeds the necessary hydraulic pressure to each of the
actuators. Accordingly, even when the engine is stopped, the
desired transmission ratio can be achieved and the clutch
engagement pressure can be maintained.
The operation state of the engine 1 is controlled by an engine
control unit 10. A brake signal from a brake switch 11, which is
caused to output an ON signal by operation of a brake pedal by the
driver; an accelerator signal from an accelerator position sensor
12 for detecting the amount by which the accelerator pedal is being
operated by the driver; a brake operation amount signal (master
cylinder pressure) from a master cylinder pressure sensor 13 for
detecting the master cylinder pressure generated based on the
amount by which a brake pedal is operated; a vehicle speed signal
from vehicle speed sensors 14 provided to each wheel; a CVT state
signal from a CVT control unit 20 described further below; and
signals representing parameters such as the engine coolant
temperature, the crank angle, and the engine rotation speed, are
inputted into the engine control unit 10. The engine control unit
10 starts, or automatically stops, the engine 1 based on the above
signals. It is also possible to use, instead of the master cylinder
pressure sensor 13, another sensor such as a depression sensor for
detecting the size of the brake pedal stroke or the force by which
the brake pedal is depressed or a sensor for detecting the wheel
cylinder pressure, and thereby detect the amount by which the brake
pedal is operated and thus detect the intention to brake on the
part of the driver.
The CVT control unit 20 transmits and receives, with respect to the
engine control unit 10, signals representing the engine operation
state and the CVT state, and controls parameters such as the gear
ratio of the belt-type continuously variable transmission 3 based
on the signals. Specifically, while a travel range is selected, the
CVT control unit 20 engages the starter clutch, determines the
transmission ratio from a transmission ratio map based on the
accelerator pedal position and the vehicle speed, and controls the
pulley hydraulic pressures. When the vehicle speed is less than a
predetermined vehicle speed, the CVT control unit 20 disengages the
lockup clutch. When the vehicle speed is equal to or greater than
the predetermined vehicle speed, the CVT control unit 20 engages
the lockup clutch and puts the engine 1 and the belt-type
continuously variable transmission 3 in a directly connected state.
When the engine is automatically stopped while the travel range is
selected, the CVT control unit 20 causes the electric oil pump 3a
to operate and secures the necessary hydraulic pressure.
Engine Automatic Stop and Restart Control
Next, a description will be given for an engine automatic stop and
restart control performed by the engine control unit 10. In the
first embodiment, when a predetermined condition is established
while the vehicle is stationary, "idling stop control", in which
engine idling is stopped, is performed. In addition, if the vehicle
is in motion but slowing down and it is determined that there is a
high probability that the vehicle will become stationary and a
transition to idling stop control will take place, coasting stop
control, in which the engine 1 is stopped, is performed.
When a normal idling-stop vehicle in which coasting stop control is
not performed is "coasting", where the vehicle is freewheeling
without the driver operating the accelerator pedal (including a
state in which the brake pedal is being operated), fuel injection
is stopped, and the engine rotation speed is maintained by a
coasting torque transmitted from the driving wheel 4 through the
lockup clutch. However, once the vehicle has slowed to a
predetermined vehicle speed, the lockup clutch is disengaged;
therefore, the engine 1 will stop unless fuel injection takes
place. Therefore, fuel injection is restarted at the point in time
at which the lockup clutch is disengaged, and the self-rotation of
the engine is maintained. Then, once it is determined that a
variety of conditions, such as the vehicle becoming completely
stationary and the brake pedal being sufficiently depressed, are
being met, engine idling is stopped.
If, in the course of restarting fuel injection from the travel
state in which fuel injection is stopped and then stopping the
engine again, the fuel consumed when the fuel injection is
restarted can be further suppressed, the fuel economy can be
improved. Therefore, an additional feature is employed in which
during coasting in an instance in which predetermined conditions
are met, coasting stop control, in which restarting of fuel
injection does not take place and the engine remains stopped (fuel
injection is not performed), is performed, and a direct transition
to normal idling stop control is made once the vehicle has become
stationary.
The condition for initiating the coasting stop control (engine-stop
condition) is that all of the following four conditions are
satisfied, and the engine-restart condition is that one of the four
conditions is not met.
1. The brake switch 11 is ON.
2. The amount by which the accelerator pedal is being operated is
zero.
3. A travel range is selected.
4. The vehicle speed is equal to or less than a reference vehicle
speed (vehicle speed at which the lockup clutch is disengaged).
The condition for initiating the idling stop control (engine-stop
condition) is that all of the following four conditions are
satisfied, and the engine-restart condition is that one of the four
conditions is not met.
1. The brake switch 11 is ON.
2. The amount by which the accelerator pedal is being operated is
zero.
3. A travel range is selected.
4. The state in which the vehicle speed is zero is maintained for a
predetermined time.
Engine Starting Device
FIG. 2 is a circuit configuration diagram of the engine starting
device according to the first embodiment. The output shaft of the
starter motor 21 is connected to the engine 1 via a belt (not
shown). A battery 22 feeds a DC current to the starter motor 21.
The inrush current limit circuit 25, comprising a resistor 23 and a
bypass relay 24 connected in parallel, is interposed between the
battery 22 and the starter motor 21. The resistor 23 keeps the
current flowing into the starter motor 21 during startup of the
starter motor 21 to a predetermined value or less. The bypass relay
24 has a normally open contact (contact a) 26, and is actuated
(i.e., the contact is closed) by a current fed from a driving relay
27. When an ignition key switch (not shown) is set to an engine
startup position ST, the driving relay 27 actuates, after a
predetermined time has elapsed, the normally open contact 26 of the
bypass relay 24 in a direction in which the normally open contact
26 closes. The predetermined is, e.g., the time at which the engine
1 is assumed to have exceeded the first upper dead center.
A coil relay 28, which is switched ON/OFF by the engine control
unit 10, is provided at a position between the battery 22 and the
starter motor 21 and further towards the starter motor 21 than the
resistor 23 or the inrush current limit circuit 25. When a request
to restart the engine 1 is made when the ignition key switch is set
to the engine startup position ST and the idling stop control and
the coasting stop control are being performed, the engine control
unit 10 switches the coil relay 28 ON, feeds power from the battery
22 to the starter motor 21, and drives the starter motor 21, until
the engine rotation speed reaches a set value (e.g., cranking
rotation speed).
FIG. 3 is a time chart showing the inrush current limiting action
by the inrush current limit circuit 25 according to the first
embodiment. At time t1, energization of the starter motor 21 is
initiated. In the above engine starting device, for a predetermined
time from the initiation of starter motor 21 energization, the
bypass relay 24 is OFF, and the inrush current limit circuit 25 is
in an ON-state. Therefore, the startup current for the starter
motor 21 is fed through the resistor 23 to the starter motor 21. It
is thereby possible to suppress a decrease in the voltage of the
battery 22 during startup of the starter motor 21 by a greater
extent than that in an instance in which the bypass relay 24 is not
present, therefore making it possible to reduce the effect on
electrical equipment and similar elements mounted on the vehicle.
At time t2, because a predetermined time has elapsed from
initiation of starter motor 21 energization or the first upper dead
center has been exceeded, the bypass relay 24 is switched from OFF
to ON, whereby the inrush current limit circuit 25 is put in an
OFF-state and the resistor 23 is short-circuited, a satisfactory
transition can be made to a cranking state in a similar manner to
conventional engine starting devices.
Bypass Relay Fault Diagnosis Process
The engine control unit 10 is provided with a fault identification
unit (fault identification means) 29 for identifying the location
of fault occurrence in the inrush current limit circuit 25 based on
the minimum voltage of the battery 22 while the starter motor is in
operation and the amount of decrease in the voltage of the battery
22 when the normally open contact 26 is actuated in the closing
direction. The flow of the bypass relay fault diagnosis process
performed by the fault identification unit 29 will now be described
using the flow chart in FIG. 4. In step S1, it is determined
whether or not the restart starter driving signal has switched from
OFF to ON; if YES, the flow proceeds to step S2, and if NO, the
flow proceeds to step S3. In step S2, as a battery voltage
initialization process, the "battery voltage minimum value A", the
"battery voltage recorded value B", and the "battery voltage
minimum value C" are initialized (i.e., subjected to a maximum
value process). The battery voltage minimum value A is the minimum
battery voltage value detected between the restart starter driving
signal switching from OFF to ON and the restart starter driving
signal switching back OFF. The battery voltage recorded value B is
the battery voltage value immediately after the bypass relay
driving signal switches from OFF to ON. The battery voltage minimum
value C is the minimum battery voltage value detected between the
bypass relay driving signal switching from OFF to ON and the bypass
relay driving signal switching back OFF.
In step S3, it is determined whether or not the restart starter
driving signal is currently ON. If YES, the flow proceeds to step
S4, and if NO, the flow proceeds to step S 10. In step S4, the
battery voltage value is read. In step S5, if the battery voltage
value read in step S4 is lower than the stored battery voltage
minimum value A, the battery voltage value is updated as the
battery voltage minimum value A. In step S6, it is determined
whether or not the bypass relay driving signal has switched from ON
to OFF; if YES, the flow proceeds to step S7, and if NO, the flow
proceeds to step S8. In step S7, the battery voltage value read in
step S4 is stored as the battery voltage recorded value B. In step
S8, it is determined whether or not the time elapsed since the
bypass relay driving signal has switched from ON to OFF is within a
predetermined period; if YES, the flow proceeds to step S9, and if
NO, the flow proceeds to RETURN.
In step S9, if the battery voltage value read in step S4 is lower
than the battery voltage minimum value C, the battery voltage value
is updated as the battery voltage minimum value C. In step S10, it
is determined whether or not the restart starter driving signal has
switched from ON to OFF; if YES, the flow proceeds to step S11, and
if NO, the flow proceeds to RETURN. In step S11, the bypass relay
fault identification process is performed, and the location of
fault occurrence is identified. In this step, it is determined
whether or not the battery voltage minimum value A is equal to or
less than the predetermined value A0, and whether or not the value
obtained by subtracting the battery voltage minimum value C from
the battery voltage recorded value B is equal to or less than a
predetermined value B0, and the fault pattern is identified from a
combination of the two determination results. The fault patterns
and the method for identifying the fault patterns will be described
further below. The predetermined value A0 is the minimum voltage of
the battery 22 while the starter motor is in operation, with
regards to the battery voltage waveform during normal operation.
The predetermined value B0 is the amount of decrease in the voltage
of the battery 22 when the normally open contact 26 is actuated in
the closing direction, with regards to the battery voltage waveform
during normal operation. The predetermined values A0 and B0 can be
obtained experimentally or otherwise in advance. The fault
identification unit 29 is provided with: an automatic stop and
restart prohibition unit (automatic stop and restart prohibition
means) 30 for stopping the idling stop system and the coasting stop
system and alerting the driver when it is determined in the above
process that a fault has occurred, and a fault information
recording unit (fault information recording means) 31 for recording
information representing the fault location. Once a fault has been
identified, the automatic stop and restart prohibition unit 30
maintains the operation stoppage of the idling stop and coasting
stop systems and the alerting of the driver until the worker has
deleted the fault information from the fault information recording
unit 31 after repairing the starting device.
Next, fault patterns and the method for identifying the fault
patterns will now be described.
Fault Pattern A
When the bypass relay 24 becomes stuck in an OFF-state (stuck in an
open state), a state is reached in which a current continues to
flow to the resistor 23 during engine startup. In a state in which
the engine friction is larger and the starting performance of the
engine 1 is poorer, e.g., during cold startup, the engine startup
time increases, a large current flows through the resistor 23 for a
long period of time, and there is a risk of the resistor 23
breaking by burning. The power supply voltage waveform
corresponding to fault pattern A has a characteristic in that, as
shown in FIG. 5A, a decrease in voltage when the inrush current
limit circuit 25 is switched from OFF to ON at time t1 does not
occur. Therefore, when A>A0 and B-C.ltoreq.B0 in step S11, the
presence of fault pattern A can be identified.
Fault Pattern B
When the bypass relay 24 becomes stuck in an ON-state (stuck in a
closed state), the resistor 23 ceases to function. Therefore, a
decrease in battery voltage at the time of engine startup can no
longer be suppressed, and the power supply to electrical equipment
fails at the time of engine startup. The power supply voltage
waveform corresponding to fault pattern B has a characteristic in
that the voltage decrease when the starter is driven is greater
than that during normal operation as shown in FIG. 5B. Therefore,
when A.ltoreq.A0 and B-C.ltoreq.B0 in step S11, the presence of
fault pattern B can be identified.
Fault Pattern C
When a disconnection occurs in the resistor 23 of the bypass relay
24, the starter cannot be started until the inrush current limit
circuit 25 is switched from OFF to ON, and when the inrush current
limit circuit 25 is switched ON, as with the instance in which the
bypass relay 24 becomes stuck in an ON-state (fault pattern B), a
decrease in battery voltage cannot be suppressed, and the power
supply to electrical equipment fails at the time of engine startup.
The power supply voltage waveform corresponding to fault pattern C
has a characteristic in that, as shown in FIG. 5C, there is no
decrease in voltage until the inrush current limit circuit 25 is
switched from OFF to ON, and the decrease in voltage during the
switching is greater than that during normal operation. Therefore,
when A.ltoreq.A0 and B-C>B0 in step S11, the presence of fault
pattern C can be identified. FIG. 6 is a list of fault modes,
bypass relay states, and voltage waveforms during normal operation
and when a fault is present.
Next, the effect of the first embodiment will be described.
(1) An engine starting device is provided in which the inrush
current limit circuit 25, comprising the resistor 23 and the bypass
relay 24 connected in parallel, is interposed between the battery
22 and the starter motor 21, and the normally open contact 26 of
the bypass relay 24 is closed at the time of engine startup. The
engine starting device is provided with a fault identification unit
29 for identifying a fault pattern based on the minimum voltage of
the battery 22 while the starter motor is in operation (battery
voltage minimum value A) and the amount of decrease in the voltage
of the battery 22 when the normally open contact 26 is actuated in
the closing direction (battery voltage recorded value B-battery
voltage minimum value C). A disconnection occurring in the resistor
23, or the normally open contact 26 of the bypass relay 24 becoming
stuck, affects the minimum voltage of the battery 22 while the
starter motor is in operation and the amount of decrease in the
voltage of the battery 22 when the normally open contact 26 of the
bypass relay 24 is actuated in the closing direction. Therefore,
looking at the minimum voltage and the amount of decrease in the
voltage makes it possible to identify the location of fault
occurrence in the inrush current limit circuit 25.
(2) The fault identification unit 29 identifies a location of fault
occurrence through a comparison with a pre-recorded normal battery
voltage waveform at the time of engine startup. In other words, the
fault pattern is identified based on a comparison between the
battery voltage minimum value A and the predetermined value A0 and
a comparison between a value obtained by subtracting the battery
voltage minimum value C from the battery voltage recorded value B
(amount of decrease in the voltage) and the predetermined value B0,
whereby it is possible to identify the location of fault occurrence
without adding a diagnostic circuit or a similar element.
(3) The fault identification unit 29 identifies the bypass relay 24
as being stuck in an open state when A>A0 and B-C.ltoreq.B0.
When the bypass relay 24 is stuck in an open state, there is a
reduction in the amount of decrease in the voltage of the battery
22 when the normally open contact 26 is actuated in the closing
direction. Therefore, using this identification method makes it
possible to identify, in an accurate manner, the bypass relay 24
being stuck in an open state due to a short-circuit or a
disconnection in the engine control unit 10, the driving relay 27,
or the bypass relay 24.
(4) The fault identification unit 29 identifies the bypass relay 24
as being stuck in a closed state when A.ltoreq.A0 and
B.ltoreq.C.ltoreq.B0. When the bypass relay 24 is stuck in a closed
state, there is an increase in the amount of decrease in the
voltage at the time of engine startup, and a reduction in the
amount of decrease in the voltage of the battery 22 when the
normally open contact 26 is actuated in the closing direction.
Therefore, using this identification method makes it possible to
identify, in an accurate manner, the bypass relay 24 being stuck in
a closed state due to a short-circuit or a disconnection in the
engine control unit 10, the driving relay 27, or the bypass relay
24.
(5) The fault identification unit 29 identifies a disconnection in
the resistor 23 when A.ltoreq.A0 and B-C>B0. When there is a
disconnection in the resistor 23, there is an increase in the
voltage effect at the time of engine startup. Therefore, using this
identification method makes it possible to identify a disconnection
in the resistor 23 in an accurate manner.
(6) An engine automatic stop and restart control device for
automatically stopping an engine 1 when a predetermined engine-stop
condition is met during coasting or when the vehicle is stationary,
and restarting the engine when a predetermined engine-restart
condition is subsequently met, wherein the engine automatic stop
and restart control device is provided with an automatic stop and
restart prohibition unit 30 for prohibiting automatic stopping and
restarting of the engine 1 and alerting the driver when a location
of fault occurrence is identified by the fault identification unit
29. It is thereby possible to avoid a circuit disconnection or a
power supply failure in electrical equipment due to operation of
the idling stop system or the coasting stop system when a fault has
occurred in the engine starting device. It is also possible to urge
the driver to perform a repair.
(7) A fault information recording unit 31 for recording information
representing the fault location identified by the fault
identification unit 29 is provided, and the automatic stop and
restart prohibition unit 30 maintains the prohibition of automatic
stopping and restarting of the engine 1 and the alerting of the
driver until information representing the fault location is deleted
after the fault location has been repaired. It is thereby possible
to definitely avoid a circuit disconnection or a power supply
failure in electrical equipment due to operation of the idling stop
system or the coasting stop system until the fault location is
definitely repaired. It is also possible to urge the driver to
perform a prompt repair, until the fault location has been
repaired.
Other Embodiments
Although a mode for carrying out the present invention has been
described above based on an embodiment, configurations other than
the present embodiment are also included in the present invention.
For example, instead of performing a comparison between the amount
of decrease in the voltage of the battery 22 when the normally open
contact 26 is actuated in the closing direction (B-C) and the
amount of decrease in the voltage during normal operation (B0), it
is also possible to constantly monitor the amount of change in the
voltage while the starter motor is in operation, and identify the
presence of fault pattern A or fault pattern B when there is no
decrease in the voltage. Also, in the embodiment, an example was
given in which the battery voltage is detected directly; however,
because there is a correlation between voltage and current from a
battery, the fault pattern may be identified based on battery
current.
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